Ore classifier



C. ALLEN.

ORE CLASSIFIER.

APPLICATION FILED NOV-5,1918.

I IV I/E IV TOR Charles/ len PatentedSept. 19, 1922.

A TTORNEK Patented Sept. 19, 1 922.

UNHTED CHAR- LES ALLEN, OF EL P-ASO, TEXAS.

ORE CLASSIFIER.

Application filed Novemberfi, 1918. Serial No. 261,191;

To all whom it may concern:

7 Be it known that I, CHARLES ALLEN, a citizen of the United States,residin at El Paso, in the county of El Paso and tate of Texas, haveinvented new and useful 'Improvement in Ore Classifiers, of which thefollowing is a specification.

This invention relates to ore milling, and

- pertains especiall vto an apparatus for classi- 10 fying themetalliferous particles coming from the mill, such apparatus beingcommonly termed an ore classifier. The func tion of a classifier is todivide the solid particles into two or more products, the particlescomposing the products difi'ering in size or weight. The classifiercommonly includes a sorting column, down through which the solidparticles fall against an upflow current to eifect classification, thesolid particles falling through the column being separated from the pulpas it comes from the mill.

As the proportion of coarse particles to fine particles variescontinually in a mill stream, constant attention would be required tovary the velocity of the rising current in the sortin column tocorrespond with the quantity of solid particles falling through it,provided the highest degree of separation was desired or possible, andprovided there is no automatic means for controllin the velocity flow ofthe rising current. rdinarily, in mill work, the valve which controlsthe upflow, is altered only for every large variation in the amount ofsolids in the sorting column.

The present invention finds its embodiment in the form of a by-pass forauto-' matically regulating or adjusting the upcurrent flow to thefalling metalliferous particles in the column, whereby to maintain asubstantially uniform velocity of flow of the upcurrent regardless ofthe volume of occupancy of the column by solid particles,

within reasonable limits.

The accom anying drawing illustrates the invention. he inflowing pulpenters at 10 and is received into a funnel 11 of a sorting column 13 andis subjected to an effect of this rising current is to break up thepulp; the lighter particles beingcarried into the overflow launder 12and the heavier particles (those which have sufiicient weight to fallagainst the rising current), fall through the sorting column 13 and intothe receptacle 14, whence they are discharged through the spigot'15.

None of the feedstream water, that is, the water coming in from thelaunder 12, passes down into the sorting column 13; all that enters thesorting column. fro-m the feed stream is the heavier particles whichhave suflicient Weight to sink out of the feed stream and into therising current in 13. The column 13 is called a sorting column becauseits function is to sort the lighter from the heavier rains. The risingcurrent which is supplied to the sorting column, enters from anysuitable source through a pipe '16, the velocity of which rising currentis controlled by the valve 17.

From the foregoing, it is apparent that when the machine is inoperation, the sorting column 13 is filled with the fresh water of theuprising current and the falling ore particles; the upflow being betweenthese solid particles in the sorting column. In other words, the areathrough which the water may pass is controlled by and to the amount of,the falling particles present. Whenever it is so contracted, thevelocity of the rising current is increased (in the absence of theby-pass 18), so that under such conditions the particles which wouldnormally fall through the sorting column cannot enter it and are carriedover into the launder 12. This is one-of the causes of poor work in anordinary hydraulic classifier.

difiiculty of loss of values by accelerated up-current flow, I providethe by-pass 18 between the receptacle 14: and the top of the sortingcolumn, the action of which by-pass is as follows? When no solidparticles are present in the sorting column, the classifying waterentering at 16 rises through 13 and 18 at the same rate and inproportion to their cross-sectional areas. When the sorting column is100 To overcome this difliculty, that is, the

partially occupied with falling Solids, its

. area is contracted, as explained above; but instead of an accentuatedupflow, that is, an

produces an automatic -balance of current flow in proportion to thefalling particles so that the same results practically are accomplishedat all times and without loss independent of the variations (of course,within usual working limits), of the amount of solids in the sortingcolumn; thus producing the same result that might be produced through aconstant regulation of the valve 17 if no by-pass were present.

The beneficial effects of this improved classifier are apparent when itis considered that with a sorting column not equipped with my automaticby-pass attachment, the velocity of the rising flow is increased 100% ifthe column is 50% occupied with solids; that if the sorting column is75% occupied with solids, the velocity of the rising flow is increased200%. The velocity. of the flow through the column is at all timesdependent upon the density in the sorting column and the density of thesorting column is in turn dependent upon the occupancy of the column bsolid articles in suspension or sinking t rough 1t.

While I haveshown the preferred form of nry invention as now known tome, it will be understood that various changes in the construction,combination and construction of parts may be made by those skilled inthe art wlthout departing from the spirit of my invention as claimed.

The density of the contents of the sorting column increasesproportionately to the occupancy of the sorting column only while thespecific gravity of the material falling through, or in suspension inthe sorting column remains constant. For instance, with a sorting column10 inches long and the fluid water with a specific gravity of 1, when nosolids are present the velocity of the rising flow is the same throughboth the column and the by-pass. The volumes are proportionate to theirrespective cross section areas. If when in operation under theseconditions, material having a specific gravity of 3 be introduced intothe column until the falling particles, or particles in suspension,occupy 50% of the volume of that part of the column between the upperand lower connecantennae tions to the by-pass, it will be occupied byflow through the by-pass, and, as long as the material causing theincreased density in the column retains a specific gravity of 3, theweight of the contents of the column and the volume of the materialoccupying the column remain relatively the same. That applies tomaterial of any given specific gravity, but, if the material of thespecific gravity of 3 be replaced in the column by the same volume ofmaterial having a specific gravity of, say, 7, the mean specific ravityof the contents of the column is a. fience the velocity head, orpressure to the flow through the bypass, is twice what it was with anequal volume of material of the specific gravity of 3 occupying thecolumn. The result is an increase of approximately 25% in the flowthrough the by-pass.

To cause a rising flow through the sorting column 13 water must beadmitted to the receptacle 14 in excess of the discharging capacityofthe spigot opening 15. The pipe 16 must be large enough to pass asuflicient volume of water but its cross-section area is dependent uponthe velocity head to the flow The relative proportionate areas andlengths of the different parts of the device will vary with theconditions under which it is to operate and the character of thematerial to be classified.

When there are no solids present in the classifier the volume of waterentering the receptacle in-excess of the discharging capacity of theopening 15 is the sole determining factor of the velocity of the risingflow through thesorting column 13 and the by-pass 18, while practicallythe sole determining factor of the velocity of the discharge through 15is the vertical height of the fluid column over 15, which is equal tothe distance from 15 to the overflow rim of the hopper. If this distancewere four feet, there would be a velocity of issuance of 192 inches persecond. 4

Assume that a three inch per second rising flow through the sortingcolumn will per square inch of cross section area.

sorting columnis such that when filled with water only the weight of thecolumn is 10 ounces per s uare inch of cross section area at its base.hen, when the density of the contents of the sorting column hasincreased to 1.5.the weight has increased to 15 ou (1)ces ne cubic inchof water at ordinary temperature weighs 0.57 64v ounces. Hence 5 ouncesequal the weight of a column of water of one square inch cross sectionarea and 8.67 inches (0.72 ft.) inheight. This additional velocity headis all effective on the flow through vthe by-pass; that is, the velocityof the flow through the by-pam from three inches to 81.7 inches persecond. At the same time, the effective velocity head to the dischargethrough 15 has been increased from 4 feet to 4.72 feet and the velocityof issuance from 192 inches to 208.8 inches per second. Therefore thevolume discharged through 15 due to an increase in the density of thecontents, of the sorting column from 1 to 1.5 cannot exceed 16.8 cubicinches per second, per square inch of cross section area.

This is the theoretical maximum and under operating conditions it isalways less.

In many cases when the devlce is classifying the volume of waterdischarged through 15 is less than when no solids are present, for thereason that the classified solid particles are discharged through 15 andby their presence diminish the area available for the outflow of water.

- ent isa by-pass whereby an increase in density of v the column by 1.In the classification of fine ores, fine coal and the like in a sortingcolumn wherein the material to be treated flows downwardly against theaction of a rising current of water, causing the lighter product tooverflow the rim of the column and the heavier product to pass outthrough a discharge orifice at the bottom of the column that step whichcomprises the by-passin o a portion of the up-flowing stream from ottomto top of tlfi column whereby to maintain a substantially uniformvelocity of flow of the up-current in the column re ardless of thevolume of occupancy of the co umn by solid particles within usualworking limits. 2. In the classification of fine ores, fine coal and thelike, the method of efi'ecting an automatic regulationof the up-flow'ofwater in a sorting column of the type disclosed which consists inproviding the column with the contents of the sorting column will act toincrease the volume of water Joy-passed, for

the purpose of maintaining a substantially uniform velocity of flow 'ofthe up-current regardless of the volume of occupancy of solid particles,within usual. working limits.

3. In a classifier for fine ores, fine coal, and the like, thecombination of a sorting column having an overflow rim and a bottomdischarge orifice, and through which the material to be separatednormally tends to flow in a downward direction, means for producing anupward current therein, and means for. establishing a second'path ofcurrent between the opposite endsof said column, whereby an increase inthe density of the contents of the sortin column will act to increasethe volume of water by-passed for the purpose of automaticallyregulating the upward current in the sorting column in accordance withthe requirements of classification.

4. In a classifier for fine ores, fine coal and the like, a classifyingcolumn, a discharge spigot at the'lower end thereof, a pulp supply spoutabove said oolumn, -means for maintaining a continuous upwardly flowingstream of clear liquid through the column, and means whereby said liquidmay be diverted in quantity proportionate to the resistance of 1tspassage through the column.

5. In a classifier for fine ores, fine coal and the" like, a verticalcolumn having an enlarged funnel-shaped mouth into which the material tobe classified may be delivered,-a receptacle inclosing the lower end ofsaid column and being provided with a restricted discharge orifice,means for continuously the like, the combination of a sorting column, afunnel at the mouth of the column into which the pulp stream to be actedupon discharges, means for delivering water to the lower end of thesorting column to create an up-flow therein to efl'ect classification, aby-pass whereby a portion of thewater that would otherwise pass throughthe sorting column, may be shunted around the sorting column back intothe funnel, whereby an increase in the density of the contents of thesorting column will act to increase the volume of water by-passed forthe purpose of automatically regulating the upward current in thesorting column inaccordance with th requirements of classification.

7. In a classifier for fine ores, fine coal, and the like, a sortingcolumn having a launder at the top, means for continuously feedingmaterial to the column at the top thereof, a receptacle at the bottom ofthe column having a restricted discharge ori-- fice, means for admittingwater tothe receptecle to eeuse em upward flew in the cellmy hand in thepresence of two subscribing 11mm, and e kg-pass exgtegdinglfrem jgtheIfiwltnesses. cetecletotetepe tecoumn orte pe t-pose of by-passing waterin varying CHARLES ALLEN 5 quantities eccerding to verietions in theden- Witnesses:

sity of the contents of the column. I W. H. BUMPER.

lintestimeny whereof I have hereunte set EDMUND SHAW.

